Penetrating instruments or needles are widely used in medical procedures to gain access to anatomical cavities ranging in size from the abdomen to small blood vessels, such as veins and arteries. Such penetrating instruments include a sharp tip or point to pierce the tissue forming a cavity wall. Once the penetrating member has been removed from the tissue, the penetrating member becomes exposed to the user or operator. An inadvertent prick after the needle is exposed to the patient's blood or body fluids can be dangerous. The transmission of pathogens from an inadvertent prick could lead to infection and diseases transmitted through the bloodstream, such as hepatitis and AIDS. Such infections may result in serious illness or even death.
A number of design approaches have been developed to prevent “needle stick” injuries. One type of device, categorized as a sliding sheath design, uses a physical barrier positioned about the needle after use. A second type of device withdraws the needle tip into a housing after use. These devices use a spring to push or pull the needle into the housing when the user activates it. But in some instances where a manual activation is required, the user may forget or simply fail to activate the needle withdrawal device. In that case, the needle is left exposed, presenting a risk to the user or caregiver.
Thus, there is a need to provide an automatic needle retraction system, one that does not require user activation, to minimize the potential risk of “needle stick” and the risk of infection and potential death associated therewith. The present invention addresses this need.